I am not sure if you have played other fighting games, so I’ll give you two answers:
Short answer: if you have played other games (especially Marvel), you can cancel moves (like the launcher) with a jump. It’s the same thing, except that in MB you can cancel most moves instead of just the launcher.
Long answer, if you are not very familiar with fighting game terms:
Recovery: the animation of an attack after it hits or a move when finishing it. For attacks, recovery is the animation where the character pulls back after attacking.
Cancel: to interrupt an attack or move’s recovery with something else. Most attacks are canceled by entering a command right after the attack hits. In Melty Blood, you can cancel most attacks with another attack. For example, you can cancel B into C by pressing C right after B hits.
Jump Cancel: similarly to how you can cancel an attack into another one, you can cancel an attack with jump. In other words, instead of pressing a button to cancel an attack with a second attack, you press up. Your character will interrupt the attack’s animation by jumping. In the air, you can jump cancel an air attack by using the air jump (also called double jump).
Dash Cancel: the same principle as canceling, but instead of pressing a button, you press forward + forward (66). Dash cancel is usually restricted to jumping attacks.
So for 2C > 5C > jc > j.A, you enter 2C, then enter 5C right after 2C hits, then press up + forward right after 5C hits (don’t wait for 5C to finish its animation), then press A in the air.
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VMan of Mana
Be prepare for the eternity battle.